In her editorial (cross-posted below), Lewis explains why she has “opted out” of the “weight-loss game.” She confides that she has been “fat” since she was a child. She still remembers the humiliations, which continue to this day– especially when she visits a primary care doctor.

It doesn’t matter whether she is seeing the physician because she has broken an ankle or needs contraception. Inevitably, he or she brings up her Body Mass Index (BMI.) And when a GP admonishes her that she should diet and work out, he rarely asks what she eats now, or how much she exercises. He doesn’t listen; he lectures.

In fact, Lewis does care about her health: she exercises regularly and has switched to a whole meal vegetarian diet. For years, she has been in good health. But her BMI remains above 30.

What Many Doctors Don’t Know—And What Even the Experts Don’t Understand

What these general practitioners don’t know is what doctors and scientists who specialize in obesity have discovered: the vast majority of overweight patients cannot shed pounds—and keep them off—even in highly controlled experimental settings where patients diet and exercise under a doctor’s supervision. As I explain in the post below two years after starting a diet, roughly 95% will have put all of the weight back on.

And even the experts who study the obesity epidemicdon’t understand why.